Conveyors of the above type are used on automatic machines, and in particular on product packing machines to transfer products between an intermittently-operated and a continuously-operated portion of the machine.
U.S. Pat. No, 4,735,032 relates to a conveyor of the above type, wherein a chain is looped about a number of pulleys, comprises equally spaced seats for receiving groups of cigarettes, and is powered by a drive pulley. The conveyor comprises one branch extending between two pulleys and operated intermittently, and a series of further branches extending between said two pulleys and operated continuously and uniformly. The two pulleys, which separate the intermittent branch from the continuous further branches, are fitted to respective slides engaging respective guides parallel to the intermittent branch, and are moved reciprocatingly in the same direction along the slides by means of a reciprocating connecting rod.
The laws of motion governing operation of the drive pulley and the connecting rod are so determined that said one branch is operated intermittently, i.e. has a succession of instants in which the branch is stopped, and the further branches are operated continuously and uniformly.
While theoretically ensuring correct operation of both the intermittent branch and the further continuous branches, the above conveyor, in actual use, has several drawbacks on account of the type of mechanism used to transmit reciprocating motion to the pulleys. That is, on the one hand, using slides and guides to guide the pulleys along respective straight courses generates considerable friction, thus resulting in wear and inaccuracy; and, on the other, seeing as most of the members for transmitting said reciprocating motion are themselves reciprocating members, the conveyor is subject to severe vibration.
Such drawbacks make the conveyor practically unusable.